Stadium: Court 4 Round: 28 Ground: Synthetic outdoor
| ITF Women Iizuka | 2016/09/28 06:20 | Sawayanagi, Riko v Mana Ayukawa | 6-2,6-4 |
| Hamamatsu, Singles W-WITF-JPN-12A | 2018/10/19 03:40 | Susan Bandecchi v Sawayanagi, Riko | 5-7,4-6 |
| Hamamatsu, Singles W-WITF-JPN-12A | 2018/10/18 01:00 | Sawayanagi, Riko v Inoue, Miyabi | 6-3,4-6,6-3 |
| Hamamatsu, Singles W-WITF-JPN-12A | 2018/10/17 04:10 | Sawayanagi, Riko v Kisa Yoshioka | 6-1,6-1 |
| ITF Women Nanao | 2018/08/29 06:40 | Shiho Akita v Sawayanagi, Riko | 6-7,6-1,7-5 |
| Tsukuba, Singles W-WITF-JPN-09A | 2018/08/21 00:30 | Sawayanagi, Riko v Momoko Kobori | 4-6,3-6 |
| ITF Women Toyota Qual | 2018/03/11 03:30 | Sawayanagi, Riko v Iwai, Mayu | 6-0,1-6,2-6 |
| ITF Women Toyota Qual | 2018/03/10 01:00 | Sawayanagi, Riko v Himari Sato | 7-5,6-0 |
| Mildura, Simples W-WITF-AUS-04A | 2018/03/06 01:05 | Maddison Inglis v Sawayanagi, Riko | 6-0,6-2 |
| Hamamatsu, Singles W-WITF-JPN-12A | 2018/10/19 01:00 | Yudanov, Marina v Mana Ayukawa | 5-7,3-6 |
| Hamamatsu, Singles W-WITF-JPN-12A | 2018/10/18 04:25 | Haruna Arakawa v Mana Ayukawa | 5-7,6-7 |
| Hamamatsu, Singles W-WITF-JPN-12A | 2018/10/17 01:00 | Mana Ayukawa v Momoko Kobori | 7-6,2-6,6-2 |
| Makinohara, Singles Qualifying W-WITF-JPN-15A | 2018/10/13 03:05 | Mana Ayukawa v Namigata, Junri | 1-6,6-3,2-6 |
| Makinohara, Singles Qualifying W-WITF-JPN-15A | 2018/10/12 03:00 | Mana Ayukawa v Susan Bandecchi | 6-4,3-6,6-3 |
| Makinohara, Singles Qualifying W-WITF-JPN-15A | 2018/10/11 00:30 | Mana Ayukawa v Ueda, Ramu | 7-5,1-6,6-2 |
| Makinohara, Singles Qualifying W-WITF-JPN-15A | 2018/10/10 00:30 | Nagi Hanatani v Mana Ayukawa | 1-6,7-5,4-6 |
| ITF Women Darwin | 2018/09/24 00:30 | Mana Ayukawa v Kyoka Okamura | 4-6,6-3,3-6 |